Pictured here is a part of the Lincoln Lab team in the clean room. (Don is in the rear, left of center.)

Where are you from?
I grew up in a little town in northern N.J., but I have lived in Needham, Mass. ever since graduate school.

"It's mind-boggling that humans can create systems that do such amazing things over such huge distances."

Describe the first time you made a personal connection with outer space.
I absolutely remember the first space missions of Alan Shepard and the rest of the Mercury 7 astronauts. It was such an exciting time! My family didn't miss a televised launch -- no matter the hour.

Being a collector type, I also started saving clippings of all the newspaper articles I could find about astronauts and space. I thought I could end up with a COMPLETE set. When the first large drawer filled up after only a few months, though, I realized that it probably wasn't going to be feasible. Of course, that was an understatement -- there have been thousands and thousands and thousands of articles about spaceflight through all sorts of media since then.

Besides this, my father was an engineer who worked on some of the engines for the X-15 aircraft. He would sometimes bring home eye-popping glossy photographs of the machines and the people involved. I thought they were just too cool -- futuristic airplanes and tough-looking guys in flight suits. I remember doing science projects describing to other fourth graders how fast the X-15 could fly. As if I truly understood ...

How did you end up working in the space program?
After completing my undergraduate and Ph.D. degrees in electrical engineering at Princeton University, I came to the Massachusetts Institute of Technology's (MIT's) Lincoln Laboratory. At Lincoln Laboratory, I wanted to be able to apply my graduate education (which had been in rather general purpose techniques and analyses concerning signals and the systems that use and process them). Such a background was relevant to a number of areas of interest at Lincoln, and so after interviewing in several of those areas, I pretty much flipped a coin and ended up working in the satellite communications area.

It turned out to be a great decision, though. It's always fun knowing that something I worked on is up there 20,000 miles or so. And within the past decade I've worked on NASA projects, which has been fantastic. These can be WAY more than 20,000 miles up there, some as much as ten THOUSAND times -- or more. It's mind-boggling that humans can create systems that do such amazing things over such huge distances.

Who inspired you?
That's a tough question. I was influenced by many people while I was growing up -- family, teachers, talented friends, and scientists and other smart and enthusiastic people I saw on television. Inspiration, though, really only came when I grew older and could appreciate at a deeper level why their accomplishments were so amazing.

What is a Lasercom System Engineer?
For the past several decades, I've worked on the technologies for systems that can take a laser beam, impose information onto it (by, say, blinking it on and off) and send it to a far-away receiver through either the vacuum of space or the atmosphere. This is done while trying to have it stay as focused as possible in order to grab a reasonable fraction of the now spread out signal (actually, a very TINY fraction). We then deduce what information has been transmitted through processing that puny amount of received light energy. We call this free-space optical communications, or sometimes laser communications or even just lasercom.

Each one of those tasks has taken many inventions over the years, and putting them all together into a useful system is a complex exercise. So from my vantage point, a lasercom system engineer decides which particular set of those inventions is best for a particular need, and then makes sure that the selections add up to a working system. For instance, a system that sends lasercom beams from a satellite orbiting Mars down to a terrestrial ground receiver will be very different from a system that sends lasercom beams between two airplanes.

Of course, when the opportunity comes to actually build one of these systems and perhaps fly one end (or perhaps both) in space, the task grows to make sure that the real pieces of glass, the real mechanisms, the real lasers, and the real electronics end up producing the results that the invention had promised in the original vision.

Tell us about a favorite moment so far in your career.
After working for 15 years in the space-based laser communications area, I was part of a real space lasercom project. I was incredibly excited to be in the operations center when it came time to turn it all on -- after four years of design, development, testing, and finally, the launch.

We waited patiently, sending commands and watching the telemetry from the radio control systems, to see if, and when, the lasercom would start to work. All of a sudden, the green light popped on; this meant that the two ends of the system had actually done everything needed to work. The lasercom link was working -- the optically-transmitted data transmitted and received perfectly! People cheered and screamed and jumped up and down and hugged -- unforgettable.

What advice would you give to someone who wants to take the same career path as you?
There is no one right path. You can do well as a specialist or as a generalist, as a work-alone person or as a team manager, as an inventor or as an implementer, as a starter or as a finisher. I would say, make sure you enjoy whatever it is you are doing and then try to do "that" well.

Perhaps even sample various "flavors" of the industry -- start some tasks, do what it takes to finish some other tasks, etc. -- in order to become an even better overall contributor. People who rise up have usually gained an appreciation for what it takes to start/finish, invent/implement, etc.

What do you do for fun?
I have played the piano since I was a child and I play whenever I have a free moment. I play all styles of music -- classical, 20th century, ragtime, theater, jazz, rock and roll ...

I am also a "sometime" musical-theater music director for local theaters; if my work schedule allows. Being a music director entails teaching and coaching all the singing as well as gathering, rehearsing and then conducting the orchestra during the performances. A great joy has been to watch both my children become experts at the piano and become theater music directors themselves.

If you were talking to a student interested in science and math or engineering, what advice would you give them?
Choose a path that gets you in touch with the best people rather than what seems to be the most interesting technology at the time, at least at the start of your education. Watch how those people work, how they think and how they attack a problem. You can then apply those good habits to whatever technology strikes your fancy later on.